Lua

Building a multipart/form-data Request for HTTP Upload

See more HTTP Examples

Uploading files to a web server typically requires building a multipart/form-data request where the files are contained in the sub-parts of the MIME request.

Note: HTTP uploads require code on the server-side to receive the upload. For example, see Complete C# ASP.NET HTTP Upload Example

This example produces the following HTTP multipart/form-data request:

POST /something HTTP/1.1
Content-Type: multipart/form-data; boundary=------------070002080409050901090203
Host: domain
Content-Length: 546

--------------070002080409050901090203
Content-Disposition: form-data; name="fileA"; filename="fileA.txt"
Content-Type: text/plain

This is the contents of file A
--------------070002080409050901090203
Content-Disposition: form-data; name="fileB"; filename="fileB.txt"
Content-Type: text/plain

This is the contents of file B
--------------070002080409050901090203
Content-Disposition: form-data; name="fileC"; filename="fileC.txt"
Content-Type: text/plain

This is the contents of file C
--------------070002080409050901090203--

Lua

local chilkat = require("chilkat")

-- This example demonstrates building a multipart/form-data request.

local req = chilkat.HttpRequest.new()

-- The ContentType, HttpVerb, and Path properties should
-- always be explicitly set.
req.http_verb = "POST"
req.path = "/something"
req.content_type = "multipart/form-data"

-- The contents and name of each file to be uploaded is provided
-- by calling any of the following methods:
-- AddBytesForUpload
-- AddBytesForUpload2
-- AddFileForUpload
-- AddFileForUpload2
-- AddStringForUpload
-- AddStringForUpload2

-- For this example, we'll provide the contents of the files to be uploaded
-- directly as in-memory strings.
req:add_string_for_upload("fileA", "fileA.txt", "This is the contents of file A", "utf-8")
req:add_string_for_upload("fileB", "fileB.txt", "This is the contents of file B", "utf-8")
req:add_string_for_upload("fileC", "fileC.txt", "This is the contents of file C", "utf-8")

-- View the request that would be sent if HttpSReq was called:
local requestMime = req:generate_request_text()
print(requestMime)

-- A few important comments about the HTTP request that is generated:
--
-- 1) Chilkat automatically generates a random boundary string.   In 99.999% of cases, this should
--    be sufficient.
-- 2) The Content-Length header is automatically generated based on the actual length of the MIME message
--    that follows the intial (topmost) MIME header.
-- 3) The HOST header will automatically get filled in with the actual domain when HttpSReq
--    is called.